That user does not exist, or the password is incorrect.

I think the issue may be with the operating system you are using. Windows XP doesn't support current SSL encryption. Please verify that you can browse to https://radmon.org on the XP machine. I suspect not. If this is the case then you may have to update your operating system, or there may be a fix out there, but I doubt it. There is a fix for Windows 7 as I had to do that a few years ago but I'm not sure there is for XP. See here:  https://duckduckgo.com/?q=windows+xp+no+https&atb=v314-1&ia=web

Can you access HTTPS, secure sites in internet explorer? Try https://radmon.org and verify you have an encrypted connection working with IE. Radlog won't work without current encryption. Try in internet explorer as this uses the PC's encryption system, not the browser. For instance, Firefox uses it's own encryption system so that will work but that is all wrapped up in Firefox. If you can't get to https://radmon.org using IE then radlog will not work on that operating system without updating the encryption cipher and root certificates, and I don't know if that can be done with XP.